Apparatus for treating end portion of sewing thread

Abstract

Apparatus for treating an end portion of a sewing thread which is supplied from a thread supplying device and is guided by a guiding device to pass near a sewing needle of a sewing head of a sewing machine, the sewing head having a front surface facing a user who operates the sewing machine, a rear surface opposite to the front surface, and a side surface connecting between the front and rear surfaces, the apparatus including a downstream holding device which holds the end portion of the sewing thread guided by the guiding device, so as to stretch a portion of the sewing thread near the sewing needle, and a cover member which covers the sewing head, the cover member providing the front, rear, and side surfaces of the sewing head, the downstream holding device being provided on a visible portion of the side surface of the cover member which portion is visible from the user facing the front surface of the cover member.

What is claimed is: 
     
       1. An apparatus for treating, before commencement of a sewing operation of a sewing machine including a threading device which puts a sewing thread through an eye hole of a sewing needle, an end portion of the sewing thread so that a predetermined length of the thread is drawn out through the needle eye, the apparatus comprising: a guiding device which guides, along a thread-guiding route passing near the sewing needle, the sewing thread supplied from a thread supplying device before the commencement of the sewing operation of the sewing machine;   said guiding device including a guiding member which is provided in said thread-guiding route and which engages the sewing thread supplied from the thread supplying device;   an intermediate holding device which is provided on a downstream side of said guiding member in said thread-guiding route and which holds the sewing thread with a biasing force applied substantially perpendicularly to the thread-guiding route;   a cutting device which is provided, on a downstream side of said intermediate holding device in said thread-guiding route, at a position around a visible side surface of the sewing machine, and which cuts off an excessive length of the end portion of the sewing thread held by the intermediate holding device, at said position distant by a predetermined distance from said guiding member in the thread-guiding route; and   a downstream holding device which is provided on an upstream side of said cutting device, and on a downstream side of said intermediate holding device, in said thread-guiding route and which holds a remaining end portion of the sewing thread cut by said cutting device,   said guiding member being movable toward the sewing needle to stretch a portion of the sewing thread in front of the needle eye, so that the sewing thread is put through the needle eye by the threading device of the sewing machine.   
     
     
       2. An apparatus for treating an end portion of a sewing thread which is supplied from a thread supplying device and is guided by a guiding device to pass near a sewing needle of a sewing head of a sewing machine, the sewing head having a front surface facing a user who operates the sewing machine, a rear surface opposite to the front surface, and a side surface connecting between the front and rear surfaces, the apparatus comprising: a downstream holding device which holds the end portion of the sewing thread guided by the guiding device, so as to stretch a portion of the sewing thread near the sewing needle; and   a cover member which covers the sewing head, said cover member providing the front, rear, and side surfaces of the sewing head,   said downstream holding device being provided on a visible portion of said side surface of said cover member which portion is visible from the user facing said front surface of the cover member.   
     
     
       3. An apparatus according to claim 2, wherein said side surface of said cover member comprises a substantially flat surface which is substantially perpendicularly connected to each of said front and rear surfaces of the cover member. 
     
     
       4. An apparatus according to claim 2, wherein said side surface of said cover member comprises a curved surface. 
     
     
       5. An apparatus according to claim 4, wherein said curved surface of said cover member comprises a part-cylindrical surface, said visible portion of said side surface comprising a front half of said part-cylindrical surface on a side of said front surface, and a portion of a rear half of the part-cylindrical surface which portion has a maximum tangent-plane angle of 30 degrees with respect to a reference plane parallel to the sewing needle and perpendicular to said front and rear surfaces parallel to each other. 
     
     
       6. An apparatus according to claim 5, wherein said visible portion of said side surface comprises a portion of said rear half of said part-cylindrical surface which portion has a maximum tangent-plane angle of 15 degrees with respect to said reference plane. 
     
     
       7. An apparatus for treating an end portion of a sewing thread which is supplied from a thread supplying device and is guided by a guiding device along a thread-guiding route passing near a sewing needle of a sewing head of a sewing machine, the sewing head having a front surface facing a user who operates the sewing machine, a rear surface opposite to the front surface, and a side surface connecting between the front and rear surfaces, the apparatus comprising: an upstream holding device which is fixed on an upstream side of the sewing needle in the thread guiding route and which holds, with a first holding force, the sewing thread supplied from the thread supplying device;   a downstream holding device which is fixed on a downstream side of said upstream holding device in the thread guiding route and which holds the end portion of the sewing thread; and   a movable holding device which is provided between said upstream and downstream holding devices in the thread guiding route and which holds the sewing thread with a second holding force smaller than said first holding force, said movable holding device cooperating with said upstream holding device to stretch a portion of the sewing thread near the sewing needle,   said movable holding device being movable away from said upstream holding device to a downstream-side position thereof so as to tension the stretched portion of the sewing thread.   
     
     
       8. An apparatus according to claim 7, wherein said downstream holding device holds the end portion of the sewing thread with a third holding force smaller than said second holding force of said movable holding device, the movable holding device being movable away from said downstream-side position thereof near to the downstream holding device, to an upstream-side position thereof so as to draw the end portion of the sewing thread held by the downstream holding device. 
     
     
       9. An apparatus according to claim 8, wherein said downstream holding device holds the end portion of the sewing thread such that not more than a predetermined length of the thread is obtained beyond the downstream holding device, said predetermined length being equal to a distance of movement of said movable holding device from said downstream-side position thereof to said upstream-side position thereof. 
     
     
       10. An apparatus according to claim 9, further comprising a cutting device which is provided at a position distant by not more than said predetermined length from said downstream holding device, and which cuts an excessive length of the end portion of the sewing thread held by the downstream holding device, so that when the movable holding device is moved from said downstream-side position thereof to said upstream-side position thereof, the cut end portion of the sewing thread is drawn out of the downstream holding device. 
     
     
       11. An apparatus according to claim 10, wherein said downstream holding device and said cutting device are provided on a visible portion of the side surface of the sewing head which portion is visible from the user facing the front surface of the sewing head. 
     
     
       12. An apparatus according to claim 7, further comprising a guiding member of the guiding device, said guiding member being provided between said upstream holding device and said movable holding device in the thread guiding route, wherein when the movable holding device is moved away from the upstream holding device to said downstream-side position thereof, the movable holding device is moved away from said guiding member and the guiding member is moved toward the sewing needle, so as to tension said stretched portion of the sewing thread. 
     
     
       13. An apparatus according to claim 12, wherein said movable holding device is provided at a position which is between said guiding member and said downstream holding device in the thread guiding route and is as high as a position of the guiding member, the guiding member and the movable holding device being movable, as a unit, downward along the sewing needle to a level of the eye hole of the needle, the guiding member being further movable to a position adjacent to the eye hole of the needle, so that the end portion of the sewing thread is put through the eye hole of the needle by a threading device of the sewing machine. 
     
     
       14. An apparatus according to claim 13, wherein said guiding member and said movable holding device are supported by a movable bar of the threading device which bar extends parallel to a vertically movable needle bar to which the sewing needle is secured, is vertically movable along the sewing needle, and is rotatable about an axis line thereof to move the guiding member toward the sewing needle and move the movable holding device away from the guiding member, the guiding device and the second holding device providing respective parts of the threading device, the movable holding device being located on a front side of said downstream holding device on which side the user operates the sewing machine. 
     
     
       15. An apparatus according to claim 7, wherein said downstream holding device comprises: at least one holding member which holds the end portion of the sewing thread;   an axis member which extends through said holding member, the end portion of the sewing thread being partially wound around said axis member; and   a biasing member which biases, with said third holding force, said holding member along said axis member toward the side surface of the sewing head, so that the end portion of the sewing thread partially wound around the axis member is held between the holding member and the side surface.   
     
     
       16. An apparatus according to claim 7, wherein said movable holding device comprises: two holding members which cooperate with each other to hold the end portion of the sewing thread;   an axis member which extends through one of said two holding members, the sewing thread being partially wound around said axis member; and   a biasing member which biases, with said second holding force, said one holding member along said axis member toward the other holding member, so that the sewing thread partially wound around the axis member is held between the two holding members.   
     
     
       17. An apparatus according to claim 16, wherein said other holding member of said movable holding device includes a horizontal portion and an inclined portion inclined downward from said horizontal portion, and wherein when the movable holding device is moved downward along the sewing needle toward a level of the eye hole of the needle, the sewing thread held by the movable holding device slides, because of an increased tension thereof, on said inclined portion of said other holding member toward said axis member, so that the sewing thread is held between said two holding members. 
     
     
       18. An apparatus according to claim 17, wherein said other holding member of said movable holding device has a thread groove which permits, when the sewing thread falls therein, the sewing thread to easily be drawn from the movable holding device, so that the end portion of the sewing thread is put through the eye hole of the sewing needle by a threading device of the sewing machine. 
     
     
       19. An apparatus according to claim 17, wherein said inclined surface of said other holding member is inclined such that when said guiding member and said movable holding device are moved as a unit along the sewing needle toward a level of the eye hole of the needle, one of opposite end portions of said other holding member which portion is nearer to the guiding member than the other end portion goes ahead of said other end portion of said other holding member which portion is nearer to said downstream holding device than said one end portion, so that the sewing thread held by the movable holding device slides, because of said increased tension thereof, on said inclined portion of said other holding member toward said axis member. 
     
     
       20. An apparatus according to claim 7, wherein said upstream holding device comprises: a holding member; and   a sheet spring which cooperates with said holding member to hold, with said first holding force, the sewing thread supplied from the thread supplying device.